Recent studies demonstrate that a significant subset of patients with bulimia nervosa have prominent winter worsening of mood and disturbances of appetite and weight regulation comparable with those observed in Seasonal Affective Disorder (SAD). SAD can be safely and effectively treated with bright light therapy. In a pilot study, 17 patients with bulimia nervosa were treated with bright light therapy (Lam, Goldner et al. 1994). They showed significant reductions in both depressive symptoms and bingeing and purging. Light therapy is low in cost and side effects compared with conventional treatments for bulimia. Relapse frequently occurs even with the best conventional treatments; so developing additional or adjunctive treatment modalities remains critical. The promising results of Lam in Vancouver, of Blouin et al. (1994) in Ottawa, and our own preliminary pilot data lead us to propose a similar study of light therapy in New York. We hope to determine whether bulimics in our geographic region can benefit from light therapy. We believe that we have improved on both Lam's and Blouin's methodology by proposing to study many more subjects for a longer treatment period, by eliminating Lam's crossover design, and by devising additional outcome measures. We propose to determine whether bright white light (10,000 lux for one- half hour daily for three winter weeks) decreases frequency of bingeing and purging in patients with bulimia nervosa. In our double-blind study, 24 female bulimics will be assigned to bright light treatment and 24 subjects to dim red light treatment. After a 2-week baseline assessment subjects will receive light treatment for 3 weeks and have 3 months of follow-up. We will use structured interviews, questionnaires and intake diaries to test our hypothesis that bright light will decrease bingeing and purging and ease winter disturbances of mood, weight, appetite, sleep, social activity and energy in bulimic subjects.